/* zmalloc - total amount of allocated memory aware version of malloc()
 *
 * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>

/* This function provide us access to the original libc free(). This is useful
 * for instance to free results obtained by backtrace_symbols(). We need
 * to define this function before including zmalloc.h that may shadow the
 * free implementation if we use jemalloc or another non standard allocator. */
void zlibc_free( void *ptr )
{
	free( ptr );
}

#include <string.h>
#include <pthread.h>
#include "config.h"
#include "zmalloc.h"

#ifdef HAVE_MALLOC_SIZE
#define PREFIX_SIZE (0)
#else
#if defined(__sun) || defined(__sparc) || defined(__sparc__)
#define PREFIX_SIZE (sizeof(long long))
#else
#define PREFIX_SIZE (sizeof(size_t))
#endif
#endif

/* Explicitly override malloc/free etc when using tcmalloc. */
#if defined(USE_TCMALLOC)
#define malloc(size) tc_malloc(size)
#define calloc(count,size) tc_calloc(count,size)
#define realloc(ptr,size) tc_realloc(ptr,size)
#define free(ptr) tc_free(ptr)
#elif defined(USE_JEMALLOC)
#define malloc(size) je_malloc(size)
#define calloc(count,size) je_calloc(count,size)
#define realloc(ptr,size) je_realloc(ptr,size)
#define free(ptr) je_free(ptr)
#endif

#if defined(__ATOMIC_RELAXED)
#define update_zmalloc_stat_add(__n) __atomic_add_fetch(&used_memory, (__n), __ATOMIC_RELAXED)
#define update_zmalloc_stat_sub(__n) __atomic_sub_fetch(&used_memory, (__n), __ATOMIC_RELAXED)
#elif defined(HAVE_ATOMIC)
#define update_zmalloc_stat_add(__n) __sync_add_and_fetch(&used_memory, (__n))
#define update_zmalloc_stat_sub(__n) __sync_sub_and_fetch(&used_memory, (__n))
#else
#define update_zmalloc_stat_add(__n) do { \
    pthread_mutex_lock(&used_memory_mutex); \
    used_memory += (__n); \
    pthread_mutex_unlock(&used_memory_mutex); \
} while(0)

#define update_zmalloc_stat_sub(__n) do { \
    pthread_mutex_lock(&used_memory_mutex); \
    used_memory -= (__n); \
    pthread_mutex_unlock(&used_memory_mutex); \
} while(0)

#endif

#define update_zmalloc_stat_alloc(__n) do { \
    size_t _n = (__n); \
    if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
    if (zmalloc_thread_safe) { \
        update_zmalloc_stat_add(_n); \
    } else { \
        used_memory += _n; \
    } \
} while(0)

#define update_zmalloc_stat_free(__n) do { \
    size_t _n = (__n); \
    if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
    if (zmalloc_thread_safe) { \
        update_zmalloc_stat_sub(_n); \
    } else { \
        used_memory -= _n; \
    } \
} while(0)

static size_t used_memory = 0;
static int zmalloc_thread_safe = 0;
pthread_mutex_t used_memory_mutex = PTHREAD_MUTEX_INITIALIZER;

static void zmalloc_default_oom( size_t size )
{
	fprintf( stderr , "zmalloc: Out of memory trying to allocate %zu bytes\n" ,
			size );
	fflush( stderr );
	abort();
}

static void (*zmalloc_oom_handler)( size_t ) = zmalloc_default_oom;

void *zmalloc( size_t size )
{
	void *ptr = malloc( size + PREFIX_SIZE);
	if (!ptr)
	{
		zmalloc_oom_handler( size );
	}
#ifdef HAVE_MALLOC_SIZE
	update_zmalloc_stat_alloc(zmalloc_size(ptr));
	return ptr;
#else
	*( (size_t*) ptr ) = size;
	update_zmalloc_stat_alloc( size+PREFIX_SIZE );
	return (char*) ptr + PREFIX_SIZE;
#endif
		}

void *zcalloc( size_t size )
{
	void *ptr = calloc( 1 , size + PREFIX_SIZE);
	if (!ptr)
	{
		zmalloc_oom_handler( size );
	}
#ifdef HAVE_MALLOC_SIZE
	update_zmalloc_stat_alloc(zmalloc_size(ptr));
	return ptr;
#else
	*( (size_t*) ptr ) = size;
	update_zmalloc_stat_alloc( size+PREFIX_SIZE );
	return (char*) ptr + PREFIX_SIZE;
#endif
		}

void *zrealloc( void *ptr , size_t size )
{
#ifndef HAVE_MALLOC_SIZE
	void *realptr;
#endif
	size_t oldsize;
	void *newptr;
	if (ptr == NULL)
	{
		return zmalloc( size );
	}
#ifdef HAVE_MALLOC_SIZE
	oldsize = zmalloc_size(ptr);
	newptr = realloc(ptr,size);
	if (!newptr)
	{	
		zmalloc_oom_handler(size);
	}
	update_zmalloc_stat_free(oldsize);
	update_zmalloc_stat_alloc(zmalloc_size(newptr));
	return newptr;
#else
	realptr = (char*) ptr - PREFIX_SIZE;
	oldsize = *( (size_t*) realptr );
	newptr = realloc( realptr , size + PREFIX_SIZE);
	if (!newptr)
	{
		zmalloc_oom_handler( size );
	}
	*( (size_t*) newptr ) = size;
	update_zmalloc_stat_free( oldsize );
	update_zmalloc_stat_alloc( size );
	return (char*) newptr + PREFIX_SIZE;
#endif
		}

	/* Provide zmalloc_size() for systems where this function is not provided by
	 * malloc itself, given that in that case we store a header with this
	 * information as the first bytes of every allocation. */
#ifndef HAVE_MALLOC_SIZE
size_t zmalloc_size( void *ptr )
{
	void *realptr = (char*) ptr - PREFIX_SIZE;
	size_t size = *((size_t*)realptr);
	/* Assume at least that all the allocations are padded at sizeof(long) by
	 * the underlying allocator. */
	if (size&(sizeof(long)-1))
	{	
		size += sizeof(long)-(size&(sizeof(long)-1));
	}
	return size+PREFIX_SIZE;
}	
#endif
	
void zfree( void *ptr )
{
#ifndef HAVE_MALLOC_SIZE
	void *realptr;
	size_t oldsize;
#endif
	if (ptr == NULL)
	{
		return;
	}
#ifdef HAVE_MALLOC_SIZE
	update_zmalloc_stat_free(zmalloc_size(ptr));
	free(ptr);
#else
	realptr = (char*) ptr - PREFIX_SIZE;
	oldsize = *( (size_t*) realptr );
	update_zmalloc_stat_free( oldsize+PREFIX_SIZE );
	free( realptr );
#endif
}

char *zstrdup( const char *s )
{
	size_t l = strlen( s ) + 1;
	char *p = zmalloc( l );
	memcpy( p , s , l );
	return p;
}

size_t zmalloc_used_memory( void )
{
	size_t um;
	if (zmalloc_thread_safe)
	{
#if defined(__ATOMIC_RELAXED) || defined(HAVE_ATOMIC)
		um = update_zmalloc_stat_add(0);
#else
		pthread_mutex_lock( &used_memory_mutex );
		um = used_memory;
		pthread_mutex_unlock( &used_memory_mutex );
#endif
	}
	else
	{
		um = used_memory;
	}
	return um;
}

void zmalloc_enable_thread_safeness( void )
{
	zmalloc_thread_safe = 1;
}

void zmalloc_set_oom_handler( void (*oom_handler)( size_t ) )
{
	zmalloc_oom_handler = oom_handler;
}

/* Get the RSS information in an OS-specific way.
 *
 * WARNING: the function zmalloc_get_rss() is not designed to be fast
 * and may not be called in the busy loops where Redis tries to release
 * memory expiring or swapping out objects.
 *
 * For this kind of "fast RSS reporting" usages use instead the
 * function RedisEstimateRSS() that is a much faster (and less precise)
 * version of the function. */

#if defined(HAVE_PROC_STAT)
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

size_t zmalloc_get_rss(void)
{	
	int page = sysconf(_SC_PAGESIZE);
	size_t rss;
	char buf[4096];
	char filename[256];
	int fd, count;
	char *p, *x;
	snprintf(filename,256,"/proc/%d/stat",getpid());
	if ((fd = open(filename,O_RDONLY)) == -1)
	{	
		return 0;
	}
	if (read(fd,buf,4096) <= 0)
	{	
		close(fd);
		return 0;
	}
	close(fd);
	p = buf;
	count = 23; /* RSS is the 24th field in /proc/<pid>/stat */
	while(p && count--)
	{	
		p = strchr(p,' ');
		if (p)
		{	
			p++;
		}
	}
	if (!p)
	{	
		return 0;
	}
	x = strchr(p,' ');
	if (!x)
	{	
		return 0;
	}
	*x = '\0';
	rss = strtoll(p,NULL,10);
	rss *= page;
	return rss;
}
#elif defined(HAVE_TASKINFO)
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <mach/task.h>
#include <mach/mach_init.h>

size_t zmalloc_get_rss(void)
{	
	task_t task = MACH_PORT_NULL;
	struct task_basic_info t_info;
	mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
	if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
	{	
		return 0;
	}
	task_info(task, TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count);
	return t_info.resident_size;
}
#else
size_t zmalloc_get_rss( void )
{
	/* If we can't get the RSS in an OS-specific way for this system just
	 * return the memory usage we estimated in zmalloc()..
	 *
	 * Fragmentation will appear to be always 1 (no fragmentation)
	 * of course... */
	return zmalloc_used_memory();
}
#endif

/* Fragmentation = RSS / allocated-bytes */
float zmalloc_get_fragmentation_ratio( size_t rss )
{
	return (float) rss / zmalloc_used_memory();
}

/* Get the sum of the specified field (converted form kb to bytes) in
 * /proc/self/smaps. The field must be specified with trailing ":" as it
 * apperas in the smaps output.
 *
 * Example: zmalloc_get_smap_bytes_by_field("Rss:");
 */
#if defined(HAVE_PROC_SMAPS)
size_t zmalloc_get_smap_bytes_by_field(char *field)
{	
	char line[1024];
	size_t bytes = 0;
	FILE *fp = fopen("/proc/self/smaps","r");
	int flen = strlen(field);
	if (!fp)
	{	
		return 0;
	}
	while(fgets(line,sizeof(line),fp) != NULL)
	{	
		if (strncmp(line,field,flen) == 0)
		{	
			char *p = strchr(line,'k');
			if (p)
			{	
				*p = '\0';
				bytes += strtol(line+flen,NULL,10) * 1024;
			}
		}
	}
	fclose(fp);
	return bytes;
}
#else
size_t zmalloc_get_smap_bytes_by_field( char *field )
{
	( (void) field );
	return 0;
}
#endif

size_t zmalloc_get_private_dirty( void )
{
	return zmalloc_get_smap_bytes_by_field( "Private_Dirty:" );
}

